1. Field of the Invention
The present invention relates to a spindle motor.
2. Description of the Related Art
A shaft fixing type spindle motor in which a shaft having strong impact resistance is fixed to a case of a hard disk driving device is generally mounted in an information recording and reproducing device such as a hard disk driving device for a server.
That is, the shaft is fixedly installed in the spindle motor mounted in the hard disk driving device for a server in order to prevent information recorded in the server from being damaged and becoming unreproducible or unreadable due to an external impact.
Meanwhile, since it is necessary for a spindle motor used for a hard disk driving device to have high reliability, maintenance of a certain amount of a lubricating fluid within a fluid dynamic bearing assembly including a fixing type shaft is required.
In addition, there is a need to develop a structure capable of managing an interface between the lubricating fluid and air so as to reduce the possibility of the fluid dynamic bearing assembly insufficiently or excessively filled with the lubricating fluid.
Further, there is a need to develop a structure capable of suppressing the lubricating fluid from being separated from a bearing clearance at the time of an external impact in order to stably maintain an amount of the lubricating fluid filling the fluid dynamic bearing assembly.